EARTH SCIENCE NOTES – Glaciers
• As recently as 15,000 years ago (a blink of the eye in geologic history), up to ______ of
Earth’s surface was covered by glaciers.
• _________ __________: a period of time when Earth was covered by glaciers.
• ______________: the lowest elevation that remains covered in snow all year.
• Ice is heavy---> it will ________________ the land beneath it. It leaves large features in
the land that we can see today.
• Ice is heavy--->it _________________. The movement of ice is called it’s ________.
Types of Glaciers
A glacier is a thick _________ mass that forms above the _____________ over hundreds or
thousands of years
1. Valley (or Alpine) Glaciers
• Ice masses that slowly advance ________ ________________ valleys originally
occupied by streams.
• stream of ice that flows between ______ ______ __________ from near the top of the
2. Ice Sheets
• _____ ____________ are enormous ice masses that flow in _____ ________________
from one or more centers and cover everything but the highest land.
• Ice sheets are sometimes called _____________________ _______ sheets because
they cover large regions where the climate is __________________ ____________.
• are huge compared to valley glaciers.
• currently cover ______________ and ___________________.
Movement of Glaciers
The movement of glaciers is referred to as___________, and it happens in two ways.
1. ____________ ___________ —involves movement within the ice
2. ___________ ___________—slipping and sliding downward due to gravity
Glaciers form where _____________ SNOW FALLS in the winter THAN CAN
___________during the summer
The glacial budget is the__________, or _______ of balance, between
___________________ at the upper end of a glacier and loss, or ______________, at the
Many landscapes were changed by the widespread glaciers of the____________ ice age.
How Glaciers Erode
• __________________—lifting of rock blocks
- _____________________________ (pulverized rock)
- ________________________- (grooves in the bedrock)
Landforms Created by Glacial Erosion
Glaciers are responsible for a variety of ________________ landscape features
1. A ____________ ______________ is _______________________ valley that was once
V-shaped but was deepen by a glacier.
2. A _________________ is a _____________________________ depression at the head
of a glacial valley.
3. Snaking, sharp-______________________ called __________________ and
4. sharp pyramid-like_______________ called____________ project above mountain
Types of Glacial Drift
• _____________ _________________ applies to all sediments of glacial origin, no
matter how, where, or in what form they were deposited.
• There are two types of glacial drift.
1. __________ is material deposited directly by the glacier.
2. ______________ ____________ is sediment laid down by glacial
Glaciers are responsible for a variety of depositional features, including
1. Moraines— ______________________________________________________
2. ______________ __________ —sloping plains consisting of deposits from
meltwater streams in front of the margin of an ice sheet
3. _____________—depressions created when a block of ice becomes lodged in
glacial deposits and subsequently melts
4. _______________ —streamlined, asymmetrical hills composed of glacial dirt
5. ____________—ridges composed largely of sand and gravel deposited by a stream
flowing beneath a glacier near its terminus
6. A __________________ is a mountain lake or pool, formed in a cirque excavated
by a glacier..
7. A _______________ ____________________- is one of a series of glacial lakes
connected by a single stream or a braided stream system.